Radio controlled lock



Feb. 2, 1965 R. WEINSTEIN 3,168,737

RADIO CONTROLLED LOCK Filed Nov. 7, 1962 FIG. /Z ffl (APAC/TY p0 Nae000,2 G TEA/VS''F/VEE 40c! j eaqzzme F/GZ X; W 23 54 12/613 Z? Z j w IIN VE N TOR 80/420 MV/VSTZ/A/ United States Patent 3,168,737 RADIOCONTROLLED LOCK Richard Weinstein, Huntington, N.Y., assignor, by mesneassignments, to Commercial Factors, Ltd, Montreal, Quebec, Canada FiledNov. 7, 1962, Ser. No. 235,932 8 Claims. (Ql. 343-225) This inventionrelates to an electronic means for operating a mechanical transducer ata distance. It has specific application for the operation of a lockwhereby access may be obtained without the use of a key or without themanipulation of a combination lock.

Prior art locks have either been operated by keys or by locks whichrequired the use of a combination to set a series of tumblers so that alock bolt can be withdrawn. The first type of lock not only requires thepossession of the key but the operator must insert it into a key holebefore the lock can be opened. The combination lock requires theknowledge of the combination and the manipulation of a dial or otherarrangement of controls which may take considerable time. The presentinvention requires the use of a small electronic circuit which can bekept in the pocket, a briefcase, or a ladys handbag. It is not necessaryto remove this circuit from the pocket in order to open the door. Theoperator with the circuit walks up to the door, puts his hand on theknob, and the door is opened immediately, thereby saving considerabletime and omitting the necessity for removing the circuit from thepocket.

One of the objects of this invention is to provide an improvedelectronic lock which avoids one or more of the disadvantages andlimitations of prior art arrangements.

Another object of the invention is to provide a lock which is secureagainst unauthorized entry but can be opened without the use of a key orthe manipulation of a combination lock.

Another object of the invention is to increase the speed of response ofa signal-operated control means.

Another object of the invention is to operate a signalcontrol mechanismwithout the use of a portable power unit.

Another object of the invention is to reduce the size of the controlcircuit so that it may be carried in the pocket of a coat or in a ladyshandbag.

The invention comprises a power transceiver which may be activated by acapacity-sensitive oscillator circuit connected to the door knob. Thetransceiver broadcasts radio waves at two frequencies and receives radiowaves at a combination modulated frequency. The arrangement is such thatthe transmitter and receiver circuits are activated in sequence so thatthe waves sent out by the combination of oscillator circuits cannot bereceived directly by a third circuit. The portable circuit carried bythe operator is a high Q reflectorwhich receives the radio power fromtwo oscillator circuits and reflects this power at the same frequenciesafter the oscillators have stopped their power broadcasts. The reflectedwaves operate the receiver circuit and open the door lock. One featureof the invention includes a free running multivibrator which transfersoperating power from the oscillators to the receiver in a sequentialmanner.

For a better understanding of the present invention, together with otherand further objects thereof, reference is made to the followingdescription taken in connection with the accompanying drawings.

FIG. 1 is a schematic diagram of the complete system showing the variouscircuit components in block form.

FIG. 2 is a capacity switch circuit connected between a door knob and arelay.

FIG. 3 is a schematic diagram showing one form of door lock which may beused with the system.

FIG. 4 is a schematic diagram of connections showing the transceiverwhich includes two oscillator circuits and a receiver circuit, eachactivated by a multivibrator.

FIG. 5 is a diagram of connections showing the reflector circuitscarried by the operator.

FIG. 6 is a series of graphs showing some of the currents and voltagespresent in the operating system.

Referring now to FIG. 1, the system includes a power transceiver 111which may be controlled for its operation by a capacity switch 11controlled by a door knob 12. The capacity switch circuit is notnecessary but it is convenient for the operation of the system since itsaves power and insures that the door will not be opened until theoperator is in a position to operate the door. The receiver portion ofthe power transceiver operates a door lock 15 only when a portablereflector circuit 14 is brought within an operating distance of thetransceiver circuit 10.

The capacity switch circuit is shown in detail in FIG. 2 and includes avacuum tube 15 with its cathode and control electrode connected to aresonant concentric line 16. The anode-cathode circuit of triode 15includes a relay having a winding 17 and a pair of contacts 18, and asource of potential 29. Because of the resonant circuit 16, there issufiicient feed-back toproduce oscillation at a high frequency. Underthe conditions of oscillation, the current through the anode circuit isreduced and contacts 18 remain in their open condition. Now, if a largeconductor such as the human body is connected to the outer end of theconcentric line (door knob 21) the resonant feedback is altered and thecircuit will stop oscillating, thereby increasing the current throughthe relay winding and closing contacts 18 to apply the potential ofsource 20 to the output terminal 22. This circuit may be replaced bymany other types of circuits such as, a push button, a lever, or anyother type of circuit arrangement which can be employed to close a pairof contacts in the permanent installation and thereby activate otherparts of the circuit.

The door lock circuit is shown in FIG. 3 and includes an input terminal23, a rectifying means 24, and some form of an amplifier element 25which may be either a transistor or a vacuum tube. The output circuit ofthe transistor 25 includes a power supply terminal 26 and a resonantcircuit 27. The resonant circuit may be connected in a number of ways,the one shown in FIG. 3 includes a capacitor 28 and an inductive winding29 which may be the primary winding of a transformer 31. having asecondary winding 31 which is connected directly to a solenoid 32 whichoperates the door bolt 33. When modulated radio waves are received bythis circuit the rectifier element 24 rectifies them and the capacitor34 removes the radio frequency components. Transistor amplifier 25amplifies the resultant current pulses and applies them to the resonantcircuit 27. If the modulation frequency corresponds to the resonantfrequency of circuit 27, power is transmitted through transformer 30 tooperate the sole noid 32 and withdraw the bolt to open the door.Terminal 26 is connected to terminal 22 for receiving power from source20.

The transceiver circuit is shown in FIG. 4 and includes a free runningmultivibrator circuit 35 having transistors 36 and 37 arranged with theusual circuit components and receiving direct current power fromterminal 38 g which is connected to terminal 22 of the capacity switchcircuit; The multivibrator circuit is well known in the art and has beendescribed in prior publications. When this circuit oscillates, thepotentials on the transistor collectors are sequentially raised andlowered at the frequency of the multivibrator operating frequency. Itshould be noted that while the potential is always high on one of thesupply conductors 40 or 41, it is never high on both of them at the sametime. This switching of operating potentials is illustrated in FIG. 6where the square-topped waves 42 are applied to conductor 40 and squaretopped waves as are applied to conductor 41.

Conductor 40 is connected to the collector electrodes of bothtransistors 44 and 45, each arranged for oscillation at a high radiofrequency. Radio frequency chokes 46 and 47 are connected in series withthese supply conductors to block the generated radio frequencies frommixing with the multivibrator circuit pulses. A resonant circuit,including a capacitor 48 and an inductor 56, is connected between thebase and emitter of transistor-44, thereby providing a feed-back circuit(with capacitor 48A) which produces oscillation at a first radiofrequency. The waves generated by this circuit and broadcast into spaceareshown in FIG. 6 as wavesSl. The second os cillating circuit,containing transistor 45, is similar 'to the first circuit except thatits resonant circuit, including capacitor 52 and inductor 53, is tunedto a second radio frequency. The result is two radio frequency wavesbroadcast for the duration of each of the waves 42. The wave forms fromthe second oscillator are not shown in FIG. 6 since they are'substantialdupiicates of forms 51. The reflector circuit 14 is shown in detail inFIG. 5. it includes two loop antennas 54 and 55, each wound on a ferritecore and each coupled to a piezoelectric crystal 56 and 57. Other formsof antennas can be used such as folded dipoles. One of the antennas andits crystal 'is tuned to the first radio frequency and the other antennais tuned to the second frequency. Each of the antennas absorbs powerfrom the broadcast waves, but because of the high Q of. the crystal, theoscillating current (and the mechanical vibrations of the crystal) buildup slowly after the start of the train of waves and, for the samereason, decay slowly afterthe end of the wavetrain. This action isillustrated by wave trains 58; in FIG. 6.

Each antenna produces a similar set of wave trains, only one of which isshown in the graph. 7

Because of the high Q of :the crystals 56 and 57, the

, antennas ring or continue to oscillate after the end of wave trains51. During this time the oscillators are cut oii but a receiver circuitas is activated by one of the square topped waves 43 applied overconductor 41. The receiver circuit includes a transistor 61 and .a tunedloop antenna having an inductor 62 and a capacitor 63, this circuitarranged for receiving both of the waves from antennas 54 and 55. Thecollector of transistor 61 is connected to terminal 64 which isconnected to input terminal 23 of the door lock circuit. Since thefrequencies of the waves from the two antennas diiier, the sum of thereceived currents produces a variable power train, the frequency of thepower variations being equal to the difference between the first andsecond broadcast frequencies. This series of wave trains is shown at 65in FIG. 6. i r

The door lock amplifier circuit (FIG; 3) is a part of the receivercircuit and includes a rectifier 24 and a'filtering capacitor'iid. Theseelements rectify the wave trains and eliminate the radio frequencycomponents, thereby producing a series of pulses 66 (see FIG. 6) havinga frequency equal to the diiierences in frequency of the two broadcastwaves. This series of pulses is applied to the resonant circuit 28, 29,in the collector circuit of transistor 25 (FIG. 3) which is adjusted forresonance at the pulse frequency and the solenoid 32 is activated towithdraw bolt 33. v

From the above description itwill be evident that the door lock can beopened only by the application of two radio waves, each having afrequency whichvcan be re ceived by resonant circuit 62, 63, and havinga dilierence l 4 V frequency which causes resonance in circuit 28, 29.Such a lock cannot be opened by an adjustable portable signal generator.Access is possible only when the reflector 14 is available or when twofrequencies are known.

Having thus fully described the invention, what is claimed as new anddesired to be secured by Letters Patent of the United States is:

l. A radio control system for operating a distant electrornechanicaltransducer comprising a power transceiver circuit including; a firsttransmitter circuit for generating and broadcasting alternatingcurrentpower at a first frequency and a second transmitter circuit forgenerating and broadcasting alternating current power at a secondfrequency; a portable double reflector in close proximity to saidtransmitter circuits for receiving saidpowerduring a broadcast timeinterval and for re-radiating a portion of the power after the end ofthe time interval; a radio receiver in said transceiver" for receivingsaid reradiated power after the end of the time interval; said radioreceiver including a first broadly tuned circuit for receiving both thefirst and second of said frequencies from the double reflector, anamplifying means, a rectifier connected to the broadly tuned circuit forrectifying the received waves, a second tuned circuit connected to therectifier responsive to current pulses having a frequency equal to thedificrence between said first and second frequencies, and a couplingmeans connected to the rectifier for applying said current pulses tosaid transducer; a source of operating power, switching means foralternately switching said source of operating power to said transmittercircuitsjduring the broadcast timeintervals and for switching said powersource to the radio receiver at the end of each of said time intervalsand means for initiating operation of saidswitching means at essentiallythe same time as said double reflector is brought in close proximity tosaid transmitter circuit.

2. A radio control systemvas claimed in claim 1 wherein saidtransceivercircuit is connected to said power source by means of a pairof relay contacts.

3. A radio control system as claimed'in claim 1 wherein said transceivercircuit is connected to said power source by means of a capacity switchcircuit which includes a resonant line, an amplifier component, and arelay, said resonant line, amplifier component, and relay beingconnected in series. 7 i q 4. A radio control system as claimed-inclairnzl wherein both of said transmitter circuits include a'resonantcircuit for determining the operating frequency, said resonant circuitseach including an inductor and a capacitor.

5. A radio control system as claimed in claim 1 wherein said portabledouble reflector inc ludes two passive antenna's, each tuned to receivethe waves broadcast' from one of said transmitter circuits. o

6. A radio control system as claimed in claim 5 wherein said antennaseach include a piezoelectric coupling component. I

7. A radio control system as claimed in claim 1 where, in said switchingmeans includes a free-running multivibrator circuit.

8. A radio control system as claimed in claim 7 wherein saidmultivibrator circuit includes two transistors with the collectorelectrode of each connected respectively to a conductor which suppliesoperating power to the receiving circuit-and'to the transmittercircuits.

NEIL C. READ, Primary Examiner.

1. A RADIO CONTROL SYSTEM FOR OPERATING A DISTANT ELECTROMECHANICALTRANSDUCER COMPRISING A POWER TRANSCEIVER CIRCUIT INCLUDING; A FIRSTTRANSMITTER CIRCUIT FOR GENERATING AND BROADCASTING ALTERNATING CURRENTPOWER AT A FIRST FREQUENCY AND A SECOND TRANSMITTER CIRCUIT FORGENERATING AND BROADCASTING ALTERNATING CURRENT POWER AT A SECONDFREQUENCY; A PORTABLE DOUBLE REFLECTOR IN CLOSE PROXIMITY TO SAIDTRANSMITTER CIRCUITS FOR RECEIVING SAID POWER DURING A BROADCAST TIMEINTERVAL AND FOR RE-RADIATING A PORTION OF THE POWER AFTER THE END OFTHE TIME INTERVAL; A RADIO RECEIVER IN SAID TRANSCEIVER FOR RECEIVINGSAID RERADIATED POWER AFTER THE END OF THE TIME INTERVAL; SAID RADIORECEIVER INCLUDING A FIRST BROADLY TUNED CIRCUIT FOR RECEIVING BOTH THEFIRST AND SECOND OF SAID FREQUENCIES FROM THE DOUBLED REFLECTOR, ANAMPLIFYING MEANS, A RECTIFIER CONNECTED TO THE BROADLY TUNED CIRCUIT FORRECTIFYING THE RECEIVED WAVES A SECOND TUNED CIRCUIT CONNECTED TO THERECTIFIER RESPONSIVE TO CURRENT PULSES HAVING A FREQUENCY EQUAL TO THEDIFFERENCE BETWEEN SAID FIRST AND SECOND FREQUENCIES, AND A COUPLINGMEANS CONNECTED TO THE RECTIFIER FOR APPLYING SAID CURRENT PULSES TOSAID TRANSDUCER; A SOURCE OF OPERATING POWER; SWITCHING MEANS FORALTERNATELY SWITCHING SAID SOURCE OF OPERATING POWER TO SAID TRANSMITTERCIRCUITS DURING THE BROADCAST TIME INTERVALS AND FOR SWITCHING SAIDPOWER SOURCE TO THE RADIO RECEIVER AT THE END OF EACH OF SAID TIMEINTERVALS AND MEANS FOR INITIATING OPERATION OF SAID SWITCHING MEANS ATESSENTIALY THE SAME TIME AS SAID DOUBLE REFLECTOR IS BROUGHT IN CLOSEPROXIMITY TO SAID TRANSMITTER CIRCUIT.